1. Field of the Invention
This invention relates in general to the recovery units for recovering refrigerant from an air conditioning system to be repaired, and in particular to such a unit having features for purging components of the air conditioning system for cleaning.
2. Description of the Prior Art
Environmental regulations now restrict the venting of refrigerant gas to the atmosphere. Repairmen working on air conditioning systems of vehicles, houses and buildings, will be required to recover the refrigerant from the system rather than simply bleeding it off to atmosphere.
Recovery units are available. A typical recovery unit has a compressor, an evaporator, and a condenser. The compressor will draw refrigerant from the air conditioning system, where it passes to an expansion valve in an evaporator to convert all of the refrigerant into a vapor. The compressor will compress the vapor, which then condenses into a liquid at the condenser. The liquified refrigerant will be stored in a tank. Typical recovery units also have means for recycling the refrigerant through a filter dryer to clean the refrigerant.
At times, it is desirable to purge components of the air conditioning system of contaminants. This has been accomplished by flowing liquid refrigerant through the component. A means to return the liquid refrigerant is required. To applicant's knowledge, existing recovery units do not have purging abilities. One patent shows a recovery unit using air compressed by the compressor to flow through the air conditioning component to purge it.